PSI - Issue 3

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F. Berto et al. / Procedia Structural Integrity 3 (2017) 85–92 F. Berto et al./ Structural Integrity Procedia 00 (2017) 000–000

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The value of the SED averaged over the control volume carefully defined as presented above, has been calculated numerically by using the FE code ANSYS 12.0  both for V-notched and semicircular notched specimens. Fig. 5 shows the synthesis based on local SED. By comparing Fig. 5 with Fig. 3 it is evident that a single narrow scatterband has been obtained by means of the local energy.

Fig. 5. Synthesis by means of local SED of multiaxial series data.

5. Conclusions A large bulk of results from multiaxial tests on V-notched and semicircular notched specimens made of 40CrMoV13.9 steel are discussed together with those obtained under pure tension and pure torsion loading from notched specimens with the same geometry. Altogether more than 120 new fatigue data (10 fatigue curves) are summarised in the present work. All fatigue data are present first in terms of nominal stress amplitudes and then re analysed in terms of the mean value of the strain energy density evaluated over a finite size semicircular sector surrounding the tip of the notch. The synthesis permits to obtain a very narrow band characterised by a scatter index equal to 1.96. The synthesis has been carried out with a constant radius independent on the loading conditions. References Atzori, B., Berto, F., Lazzarin, P., Quaresimin, M., 2006. Multiaxial fatigue behaviour of a severely notched carbon steel. International Journal of Fatigue 28, 485-493. Ayatollahi, M.R., Razavi, S.M.J., Chamani, H.R., 2014a. Fatigue Life Extension by Crack Repair Using Stop-hole Technique under Pure Mode-I and Pure mode-II Loading Conditions. Procedia Engineering 74, 18–21. Ayatollahi, M.R., Razavi, S.M.J., Chamani, H.R., 2014b. A numerical study on the effect of symmetric crack flank holes on fatigue life extension of a SENT specimen. Fatigue & Fracture of Engineering Materials & Structures 37(10), 1153-1164. Ayatollahi, M.R., Razavi, S.M.J., Yahya, M.Y., 2015a. Mixed mode fatigue crack initiation and growth in a CT specimen repaired by stop hole technique. Engineering Fracture Mechanics 145, 115-127. Ayatollahi, M.R., Razavi, S.M.J., Rashidi Moghaddam, M., Berto, F., 2015b. Mode I fracture analysis of Polymethylmetacrylate using modified energy—based models. Physical Mesomechanics 18(5), 53-62. Ayatollahi, M.R., Rashidi Moghaddam, M., Razavi, S.M.J., Berto, F., 2016. Geometry effects on fracture trajectory of PMMA samples under pure mode-I loading. Engineering Fracture Mechanics 163, 449–461. Ayatollahi, M.R., Razavi, S.M.J., Sommitsch, C., Moser, C., 2017. Fatigue life extension by crack repair using double stop-hole technique, Materials Science Forum 879, 3-8. Berto, F., Lazzarin, P., Yates, J., 2011. Multiaxial fatigue of V-notched steel specimens: a non-conventional application of the local energy method. Fatigue and Fracture of Engineering Materials and Structures 34, 921–943.